The present invention relates to a solid-state image pickup apparatus which adopts a face-down packaging (face-down bonding) so as to mount a solid-state image pickup device, and to a manufacturing method thereof.
Conventionally, as shown in FIG. 13, a solid-state image pickup apparatus 100 has a structure in which a solid-state image pickup device 102 is fixed to a package 101, and the solid-state image pickup device 102 and the package 101 are connected by wiring, using Au wires 103, and a light receiving portion of the solid-state image pickup device 102 is sealed with a transparent substrate 104 of glass, optical filter and the like. This structure is generally called a xe2x80x9cwire bonding structurexe2x80x9d.
However, in order to prevent a short-circuit defect on the Au wires 103 for connecting an electrode terminal 105 of the package 101 with an electrode terminal 106 of the solid-state image pickup device 102, it is required that the solid-state image pickup apparatus 100 of the wire bonding structure provides a wire loop so that it has a space in a direction of height, and the adjacent electrode terminals 105 of the package 101 have a wide pitch therebetween, thus being difficult to attain a compact and thin solid-state image pickup apparatus. Since there is a limit in attaining a compact and thin solid-state image pickup apparatus by the solid-state image pickup apparatus 100 having the foregoing structure, a solid-state image pickup apparatus disclosed, for example, in Japanese Unexamined Patent Publication No. 204442/1994 (Tokukaihei 6-204442 published on Jul. 22, 1994) adopts the following structure. That is, as shown in FIG. 14, a solid-state image pickup apparatus 110 adopts face-down packaging for mounting a solid-state image pickup device 112 by making a surface thereof face a surface of a transparent substrate 111 so as to directly equip the transparent substrate 111 with the solid-state image pickup device 112, thereby attempting to realize a compact and thin solid-state image pickup apparatus.
Thus, the conventional solid-state image pickup apparatus 110 including the solid-state image pickup device 112 on the transparent substrate 111 by direct face-down packaging has a great advantage in realizing a compact and thin solid-state image pickup apparatus. However, electric signal external input/output (I/O) terminals 113 on the transparent substrate 111 are disposed to point a side of light receiving surface of the solid-state image pickup device 112, and therefore, the conventional solid-state image pickup apparatus 110 has such a problem that a highly developed assembly technique is required so as to integrate the solid-state image pickup apparatus 110 into peripheral devices.
Namely, the solid-state image pickup apparatus 110, though miniaturized and thin, is so small that its workability is poor. Therefore, it is necessary to utilize a large-scale apparatus so as to allow thus small mounting component to be recognized as an equipment, and determine a mounting position, etc. This, as a result, raises such problems as to require higher development or complication of, and an increase in the cost of, an apparatus for mounting. More specifically, under such circumstances as above, in order to assemble components into an apparatus, it is necessary either to increase the manpower or to automate the assembly.
However, in fact, increasing the manpower is difficult, and the automation of the assembly requires large-scale devices such as a position recognizing device. That is, adopting either of the above means results in a problem of a large increase in costs.
Meanwhile, generally, a solid-state image pickup device is different from a normal semiconductor device in terms of dealing with an optical signal, i.e., an image. Moreover, on a surface of the solid-state image pickup device is formed organic components such as a color filter and a micro lens. Consequently, it is preferable that the surface of the solid-state image pickup device be hermetically sealed so as to prevent dusts, etc. In addition, most careful attention should be paid in the manufacturing steps of bonding and mounting assembly.
Therefore, during these manufacturing steps, it is required to prevent dusts and blemishes, and a bump or resin from being pressed out to a light receiving portion.
In this respect, the conventional solid-state image pickup apparatus 110 shown in FIG. 14 has the following problems with regard to the bonding of projecting electrodes 114, resin setting at the time of face-down packaging of the solid-state image pickup device 112, dust disposing process at the time of face-down packaging.
First, when bonding the projecting electrodes 114, as shown in FIG. 14, at the time of the face-down packaging of the solid-state image pickup device 112, a conductive adhesive 116 is used to join the projecting electrodes 114 of the solid-state image pickup device 112 to an inner wiring metal layer 115 of the transparent substrate 111. In that case, the conductive adhesive 116 is applied in a state of dots to the projecting electrodes 114. This raises a problem of complication of the manufacturing step of bonding the projecting electrodes 114.
Meanwhile, as to the setting of resin at the time of face-down packaging of the solid-state image pickup device 112, projecting frame resins 118 which are different from seal resin 117 are arranged to remain inside of the projecting electrodes 114 without being set. When the seal resin 117 is applied for sealing in the following step, the projecting frame resins 118 play a role as a stopper which prevents the seal resin 117 from being pressed out. Further, in the solid-state image pickup apparatus 110, the conductive adhesive 116 and the projecting frame resins 118 are set by an application of heat simultaneously with the setting of the seal resin 117. For this reason, there arises problems such as the complication of, and an increase in, manufacturing processes at the time of face-down packaging.
Next, as to a problem of dusts at the time of face-down packaging, in the solid-state image pickup apparatus 110, a surface of the solid-state image pickup device 112 is hermetically sealed simultaneously with the face-down packaging.
Accordingly, in addition to a problem of a high probability of adhesion of dusts due to many steps of applying a resin, the adhered dusts cannot easily be removed. Further, since the resins are not yet set, there is such a problem that they are pressed out with respect to the inside of the light receiving surface.
It is an object of the present invention to provide a solid-state image pickup apparatus capable of reducing man-hours in bonding, improving bonding quality, and being readily integrated into peripheral devices, and a manufacturing method of the solid-state image pickup apparatus.
In order to attain the foregoing object, the solid-state image pickup apparatus according to the present invention includes: a transparent substrate having an inner wiring metal layer and an electrode terminal group for outputting an electric signal to the outside; a solid-state image pickup device in which each first projecting electrode corresponding to the inner wiring metal layer of the transparent substrate is formed on each surface electrode; and a print board of non-pin type lead terminal structure including an aperture which is as large as the solid-state image pickup device, wherein: the transparent substrate includes second projecting electrodes which are respectively formed on electrode terminals of the electrode terminal group, the transparent substrate and the solid-state image pickup device are bonded by face-down packaging, and the inner wiring metal layer of the transparent substrate and the each first projecting electrode of the solid-state image pickup device are connected by ultrasonic bonding, and the transparent substrate and the print board are electrically connected at the each second projecting electrode of the transparent substrate, and joined so that a light receiving portion of the solid-state image pickup device is hermetically sealed with a thermosetting resin.
With the foregoing invention, the transparent substrate having the inner wiring metal layer and the electrode terminal group for outputting an electric signal to the outside, and the solid-state image pickup device in which each the first projecting electrode corresponding to the inner wiring metal layer of the transparent substrate is formed on each surface electrode, are bonded by face-down packaging. Therefore, a compact and thin solid-state image pickup apparatus, the size of which is closer to outer dimensions of the solid-state image pickup device than the size of a solid-state image pickup apparatus adopting wire-bonding, can be realized. Note that, the inner wiring metal layer may be formed of, for example, an insulating thin film and a conductive thin film, which are stacked.
Here, in the present invention, the inner wiring metal layer of the transparent substrate are connected with each the first projecting electrode of the solid-state image pickup device by ultrasonic bonding.
That is, in the case of a conventional face-down packaging, the first projecting electrodes of the solid-state image pickup device and the inner wiring metal layers of the transparent substrate were electrically connected by dotting the first projecting electrodes with the conductive adhesive, thus resulting in problems such as a complication of manufacturing steps and an increase in man-hours.
However, in the present invention, ultrasonic bonding is adopted to connect the inner wiring metal layers of the transparent substrate and the first projecting electrodes of the solid-state image pickup device. The ultrasonic bonding is such a method as to apply pressure and ultrasound to joint portions among the inner wiring metal layers and the first projecting electrodes so as to perform solid-state welding, and thus simplifying and ensuring the joint.
Further, in the present invention, the second projecting electrodes are respectively formed on the electrode terminals of the electrode terminal group of the transparent substrate, and to the transparent substrate is joined a print board having a frame aperture which is as large as the solid-state image pickup device and a non-pin type lead terminal structure, by electrically connecting each second projecting electrode of the transparent substrate and by hermetically sealing a light receiving portion of the solid-state image pickup device with a thermosetting resin.
That is, conventionally, the solid-state image pickup device and the transparent substrate were simply bonded by the face-down packaging, and therefore, the electrode terminal group of the transparent substrate was pointed toward the side of the solid-state image pickup device, and furthermore, since this portion of the electrode terminal group is a small area, there was such a problem that connection for outputting an electric signal from the electrode terminal group to the outside was difficult.
However, in the present invention, the electrode terminal group of the transparent substrate is connected with the print board having the non-pin type lead terminal structure via the second projecting electrodes respectively formed in the electrode terminal group.
Accordingly, a signal to the outside can be outputted via the non-pin type lead terminals which are formed on the print board, and as a result, the signal can be outputted in a separate place from the solid-state image pickup device.
As a result, the output from the transparent substrate, i.e., the output from the solid-state image pickup device can readily be obtained, and therefore, when the present solid-state image pickup apparatus is integrated into external peripheral devices, a solid-state image pickup device which does not require any exceptional integrating technique and which is easily dealt with can be provided.
Further, in the present invention, the print board and the transparent substrate are bonded with the thermosetting resin, and in that case, an electric connection between the print board and each the second projecting electrode of the transparent substrate is surely maintained.
Furthermore, the print board and the transparent substrate are bonded by hermetically sealing the light receiving surface of the solid-state image pickup device with the thermosetting resin.
As a result, only one application of the thermosetting resin is sufficient for hermetic seal, thereby reducing man-hours. Further, as a result, the process of face-down packaging can be performed in a short period of time, thereby reducing possibilities of allowing entry of dirt between the solid-state image pickup device and the transparent substrate and allowing the dirt to damage the light receiving portions of the solid-state image pickup device.
Further, in the present invention, the thermosetting resin is arranged not to be applied in advance in order to prevent a seepage of a thermosetting resin yet to be set into the light receiving portions of the solid-state image pickup device, thus preventing the seepage of the thermosetting resin yet to be set and previously applied into the light receiving portions.
As a result, the solid-state image pickup apparatus capable of reducing man-hours in bonding, improving bonding quality, and being readily integrated into peripheral devices can be provided.
Further, in order to attain the foregoing object, the manufacturing method of the solid-state image pickup apparatus according to the present invention includes the steps of: (i) performing face-down packaging by disposing an inner wiring metal layer phase of a transparent substrate to face a surface electrode phase of a solid-state image pickup device, and connecting first projecting electrodes on the surface electrode phase and inner wiring metal layers of the transparent substrate by ultrasonic bonding; (ii) applying a thermosetting resin to peripheries of each second projecting electrode to be formed in an electrode terminal group on the transparent substrate, and of the solid-state image pickup device; (iii) fixing by pressing a print board, which has an aperture which is as large as the solid-state image pickup device and a non-pin type lead terminal structure, onto the transparent substrate so as to connect the each second projecting electrode of the transparent substrate and each non-pin type lead terminal of the print board, and simultaneously performing hermetic sealing of a surface portion of the solid-state image pickup device with a thermosetting resin; and (iv) applying heat to set the thermosetting resin.
With the foregoing method, face-down packaging is performed by disposing the inner wiring metal layer phase of the transparent substrate to face the surface electrode phase of the solid-state image pickup device. When performing face-down packaging, each the first projecting electrode of the solid-state image pickup device and the inner wiring metal layer of the transparent substrate are connected by ultrasonic bonding.
Next, the thermosetting resin is applied the peripheries of the second projecting electrodes of the transparent substrate and of the solid-state image pickup device, then, the transparent substrate is fixed by pressing it against the print board having the frame aperture which is as large as the solid-state image pickup device, and the non-pin type lead terminal structure, thereby connecting the second projecting electrodes of the transparent substrate and the non-pin type lead terminals of the print board. Here, simultaneously, the surface portion of the solid-state image pickup device is hermetically sealed with the thermosetting resin which is set by the application of heat.
As a result, the solid-state image pickup apparatus can be manufactured in a short period of time, where tasks in the manufacture are simple. In addition, the complete solid-state image pickup apparatus has high bonding quality, which can readily be integrated into peripheral devices via the print board having the non-pin type lead terminal structure.
Consequently, the manufacturing method of the solid-state image pickup apparatus capable of reducing man-hours in bonding, improving bonding quality, and being readily integrated into peripheral devices can be provided.
Additional objects, features, and strengths of the present invention will be made clear by the description below. Further, the advantages of the present invention will be evident from the following explanation in reference to the drawings.